The invention relates to a process for producing a two-chamber pressurized package having an outer body which encloses an interior space, which can be subjected to pressure, and forms an opening through which an inner body of a material which can fold or be crumpled is inserted.
As a rule, two-chamber pressurized packages of this kind are today used to replace the known pressurized containers employing a propellant gas. The medium is dispensed from the inner body by the subjection to pressure of the interior space of the outer body. The medium to be dispensed therefore does not come into contact with this pressure medium but is forced out through a valve by alteration of the inner body.
These known two-chamber pressurized packages essentially comprise three parts, namely the outer body, for example an aluminum sleeve having a base, the inner body, for example a very thin aluminum sleeve and a funnel which is placed on the orifice edge of the inner and outer body and surrounds the latter sealingly. The appropriate valve is then inserted centrally in this discoid funnel.
It is precisely the fitting of the funnel onto the orifice edges of the inner and outer body which requires a considerable amount of work, since this has to be done by hand. The funnel is rolled or flanged together with the orifice edges. It therefore requires a certain space. Since the valve itself in general likewise requires a diameter of 25 mm, the openings of the present-day two-chamber pressurized packages necessarily have a total diameter of about 40-65 mm. In between, only two-chamber pressurized packages having stepped dimensions are used.
The inventor has set himself the object of developing a process of the type mentioned above by means of which the fitting of the additional funnel is made superfluous, in which the interior space of the outer body is kept absolutely leakproof and in which two-chamber pressurized packages having various opening diameters can be produced, starting from as low as 1 inch, i.e. 25.4 mm.
SUMMARY OF THE INVENTION
This object is achieved by the fact that, prior to flanging, or the like, of the opening, filling of the inner body and fitting of a valve in the region of the orifice, the outer body and inner body are connected to one another in a predetermined region and are then folded over together to form a flanged edge.
This means that a leak-free connection between the inner body and outer body is produced even before the flanged edge is produced and hence that the interior space, which can be subjected to pressure, is kept absolutely leakproof.
The connection is preferably effected by welding, adhesive bonding, deformation or the like. The best solution here has proved to be a coating which is applied either to the outer body or to the inner body or to both in the connecting zone prior to the insertion of the inner body into the outer body. This coating, for example a suitable adhesive, can then dry, so that the inner body is inserted into the outer body without any alteration to the coating. After insertion, the two-chamber pressurized package preferably passes through an oven, in which the coating is liquefied. A certain connection is thereby produced already between the inner body and outer body. Since, however, in general, the inner body maintains a certain distance from the outer body so that, in the use position, it can be surrounded by sufficient pressure medium, it has proved to be advisable to introduce a tool into the opening of the two-chamber pressurized package, via which tool the inner body is pressed against the outer body in the appropriate connecting zone. This tool can be heated in order that the liquefaction of the coating may be effected or maintained by means of this heat.
Following the production of the connection between the inner body and outer body, the orifice edges are then flanged, this preferably being accomplished by rolling.
The inner space is henceforth absolutely leakproof. If leaks should occur, contrary to expectations, in the region of the connection, additional sealing material can be introduced through the opening which also serves for the subjection to pressure of the inner space, which then flows along the inner walls of the outer body and thus supplements the coating of the connecting zone.
In the final operation, all that is required now is for the two-chamber Pressurized package to be filled with the medium to be dispensed and for the valve to be fitted on, by means of which the inner body space is then also sealed, and for the propellant gas to be fed in via a hole in the base. This process in accordance with the invention furthermore has the advantage that both the outer body and the inner body can be given their final print, finish or the like even before flanging. Furthermore, in contrast to the hitherto conventional funnels, all standard internal protection finishes can be used. Flanging can be effected by means of an automatic machine, thus making considerable savings in terms of labor.
Furthermore the cutting edges of the outer body and of the inner body are hidden in the flanged edge or in the inside of the two-chamber pressurized package. According to this arrangement they do not corrode.
In an improved embodiment of the invention, a sealing compound covers the area of the flanged edge in which the folded edge contacts the inner surface of the inner body or lies partly on the inner body. The sealing compound is exposed to the inner pressure of the two-chamber pressurized package so that the cutting edges are absolutely isolated and the space between the outer body and the inner body is sealed. Furthermore the inwardly folding of the flanged edge has the important advantage that the contact height and the height of the pressurized package can be determined more exactly. It is not necessary to mill the outer sealing surface.